They paused their usual wars between each other to repel thePersians, then went back to fighting with increased ferocity afterthe Persian agreed to peace. Athens converted the Delian Leagueinto an empire of its own, lived high on the proceeds, and used themilitary and naval strength to try to dominate the Greek world.This resulted in the davastating 27-year Peloponnesian War whichAthens lost and was stripped of its empire. Inter-Greek arfarecontinued on for another 50 years, giving Macedonia the chance totake control of the debilitated Greek city-states.